Journey with Jaundice: A Narrative Review on the Global Health Perspective of Hepatitis A Virus and its Impact on the Modern World

The viral aetiology of pandemic jaundice remained elusive until the mid-twentieth century. Hepatitis A virus (HAV) was recognised as a distinct entity from other varieties of hepatitis during the second World War. The prevalence of HAV has varied largely across geography and time. Locations with poor sanitation and crowded living conditions prove suitable for the emergence of HAV infections with travel-related outbreaks spreading the disease worldwide. HAV transmission occurs via ingestion of contaminated food or water, or direct contact with an infected individual. HAV can cause liver failure and rarely death especially in the older persons and those with chronic liver disease. Use of BSL-2 facility, PPE combined with administration of HAV immune globulin and/or inactivated HAV vaccines are needed for laboratory workers. HAV is an non-enveloped picornavirus with 7.5 kb positive-sense single-stranded RNA. Three genotypes infect non-human primates, and four infect humans. Each genotype’s strains share ≥85% nucleotide identity. The primary capsid proteins are encoded by the amino terminal one-third of the viral genome, whereas the remaining two-thirds encode nonstructural proteins necessary for viral replication. Viral protease proteolytically processes translated viral proteins. Virions enter the liver via the portal circulation and are taken up by hepatocytes where they proliferate and are released into the bile duct. The virus’s enterohepatic cycles persist until neutralising antibodies break them. Hepatocellular degeneration, apoptotic alterations, inflammation and hepatocyte regeneration are essential histopathological characteristics of acute hepatitis. Methods like reverse transcriptase PCR (RT-PCR) amplification, DNA-RNA hybridisation and radioimmunoassay (RIA) detect and differentiate HAV viral strains. The discovery of sensitive anti-HAV IgG tests that can quantify antibodies in saliva following immunisation seems promising. A recombinant HAV antigen would be cheaper in the future compared to HAV generated in tissue culture.